Mayon Volcano is showing heightened activity, and people are asking why Taal and Kanlaon volcanos are acting up at the same time.
“Are they connected?” asks an academician who confesses that she has “a thing” for volcanos and that she is “enthralled” by movies on volcanos and the Jules Verne novel “Journey to the Center of the Earth.” Many others are as concerned and speculating on the supposed connections of the three volcanos, with no less than President Ferdinand Marcos Jr. trying to allay their fears by saying that “the government is closely monitoring the situation.”
Public anxiety over the simultaneous volcanic activity was sparked by recent pronouncements. Last June 8, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported that it had raised Mayon’s Alert Level to 3, which means an increased tendency to a hazardous eruption. At the same time, Taal was reported to have recently increased its sulfur dioxide emissions, a constituent of volcanic smog that has affected the health of some residents. To add to the panic, flights above Kanlaon have been prohibited since June 6 due to the risk of volcanic activity.
All these reports may seem like the early signs of an apocalypse. But viewed with the proper perspective and context on the demeanor of volcanos, these events are not extraordinary.
Are Mayon, Taal and Kanlaon directly related? The answer is no. Each belongs to a group specific to origin: Mayon is part of the Bicol Volcanic Arc; Taal, of the Luzon Volcanic Arc; and Kanlaon, of the Negros Volcanic Arc. The Bicol, Luzon and Negros Volcanic Arcs were formed due to distinct geological processes related to activity along the Philippine Trench, Manila Trench and Negros Trench, respectively. Thus, in terms of their evolution, the three volcanos are entirely different from one another.
To easily remember this geological fact, one may think of Mayon, Taal and Kanlaon as coming from different families with distinct lineages and unique DNA.
According to the United States Geological Survey, there is no definitive evidence that the eruption of one volcano can trigger the eruption of another hundreds of kilometers away, or in a different continent. Mayon, Taal and Kanlaon are more than 300 km apart. Without evidence to link their current activities, there is no scientific basis to say that their respective behaviors are connected.
The Smithsonian Institute’s Global Volcanism Program (GVP) calculates an average of 20 volcanos erupting daily worldwide, and classifies 40 to 50 under a continuing-eruption status, meaning intermittent eruptive events without a break of three months or more.
The weekly volcanic activity reports of the Smithsonian’s GVP identify Taal Volcano as in a continuing eruption. Following the logic governing the analysis of the current states of Mayon, Taal and Kanlaon, it is perhaps safe to say that the frenzied activity of certain volcanos worldwide is not connected.
There are some remarkable examples in which the simultaneous eruptions of volcanos were connected. But unlike the currently active volcanos in the Philippines, all these historic cases involved volcanos that were within 10 km of each other. When volcanos are close to each other and share a common underground reservoir of magma (hot molten rock), an eruption can trigger a nearby volcano’s unrest.
Such was the case involving Papua New Guinea’s Tavurvur stratovolcano and Vulcan cone, which are about 6 km apart. Both are part of the Rabaul Caldera and share the same volcanic plumbing system. In 1994, Tavurvur and Vulcan erupted simultaneously, killing five persons. A twin eruption of Tavurvur and Vulcan in 1937 killed 508 persons.
However, not all volcanos that are near each other exhibit the same behavior as the Rabaul Caldera volcanos. In Hawaii, for example, Kilauea Volcano is located 33 km away from the summit of Mauna Loa Volcano. Kilauea is even nested on the flank of Mauna Loa, which is immense in terms of volcano size. Since their plumbing systems are different and they tap magma from different reservoirs, these two volcanos have not been historically observed to trigger each other’s eruptions.
The hype in social media lists even Bulusan Volcano, which is under Alert Level 0, among the currently restless volcanos in the Philippines. Alert levels on a scale of 0 to 5 are assigned to all the volcanos that are continuously monitored by Phivolcs, which include Mayon, Taal, Kanlaon and Bulusan.
In general, Alert Level 0 means that the volcano is exhibiting typical behavior or background levels in terms of monitored earthquake activity, gas emissions, and other parameters that can indicate an imminent hazardous eruption. The alert level is raised when monitored indicators for an eruption increase, and is lowered when they decrease. Alert Level 5 means that there is an ongoing hazardous eruption.
The alert level scheme is unique to a particular volcano and requires corresponding actions on the ground. For their safety, those who live in the shadow of any active volcano should memorize and internalize the actions required by these alert levels.
A quick look at the alert levels shows that all these active volcanos in the country, except for Mayon, are under Alert Level 1, which means that it is exhibiting a low level of unrest (Figure 1). Kanlaon and Bulusan have been on Alert Level 1 for several years. Taal has been on low alert for almost a year and is only continuing its eruptive activity that began when it suddenly awoke on Jan. 12, 2020, after more than 43 years of sleep.
These lead us to conclude that the information used to raise the notion of connectedness in the current activity of at least three volcanos in the Philippines was selective and without real evidence.
Mayon’s status has recently been raised to Alert Level 3 because of lava reaching its summit. As more lava is pushed to the surface, the newly formed lava dome collapses in increments, spewing chunks of hot rocks down steep slopes. At night, these appear as a spectacular bright red glow against the silhouette of Mayon’s perfect cone. It will become more deadly and, at the same time, more dazzling if Alert Level 5 is reached.
If they can, readers can travel to the province of Albay to help the affected communities and watch world-renowned Mayon, a textbook example of a stratovolcano, the archetypal volcanic beauty, in all its splendor. Not all people are blessed with the opportunity to be part of such a dramatic event. Be safe, and don’t worry too much about the background noise from other volcanos. There is no evidence to link them.
AMF Lagmay is a professor at the National Institute of Geological Sciences, University of the Philippines, and the executive director of the UP Resilience Institute and NOAH Center. He thanks his children Amaya, Andres and Lucas Lagmay for their research on the alert levels of Mayon, Taal and Kanlaon volcanos. —Ed.